<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        .box{
            font-size: 16px;
            border: solid 1px #ddd;
            width: 300px;
            padding: 10px;
            margin-bottom: 2rem;
            word-wrap: normal;
        }
        .break{
            word-wrap: break-word;
        }
    </style>
</head>
<body>
    <h1>word-wrap</h1>
    <h2>normal</h2>
    <div class="box normal">
        normal： 允许内容顶开或溢出指定的容器边界aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
    </div>

    <h2>break-all</h2>
    <div class="box break">
         break-word： 内容将在边界内换行。如果需要，单词内部允许断行aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
    </div>
</body>
</html>